php - Iterating through the first 30 keys in an array -

i have array stored variable called $data

["data"]=>   array(413) {     [0]=>     object(stdclass)#254 (7) {       ["energy"]=>       string(7) "44555"       ["closing"]=>       string(10) "102"     }     [1]=>     object(stdclass)#260 (7) {       ["energy"]=>       string(7) "2522"       ["closing"]=>       string(10) "854"     } 

and obtain arithmetic mean closing values this:

// initialize sum , total $sum = 0; $total = 0;  foreach ($data->data $obj) {     if (isset($obj->closing)) {   // verify current object has closing         $sum += $obj->closing;    // add sum         $total++;                  // increment count     } } echo $sum / $total;                // display average 

the problem need first 30 key array, don't know how that, can me please? have tried loop doesn't trick. ideas? thank in advance time , help.

using second piece of code :

$sum = 0; $total = 0;  foreach ($data->data $obj) {     if (isset($obj->closing) && $total < 30) {   // closing? + numofvalues < 30 ?         $sum += $obj->closing;         $total++;     } }  // display average echo $sum / $total; 

adding && $total < 30 should trick since count how many items add.

---

can break out of for if don't want loops single condition :
(thanks adam pointing out)

foreach ($data->data $obj) {     if (isset($obj->closing) && $total < 30) {         // ...     }     else if ($total >= 30) break; }